Purpose :
Sorsby fundus dystrophy is a rare autosomal dominant disease characterised by bilateral loss of central vision in the third-fifth decade attributed to choroidal neovascularisation. To date there is no definitive treatment, however, several case reports have documented the use of anti-vascular endothelial growth factor antibodies (anti-VEGF) to maintain vision. We describe the first long-term study of the use of anti-VEGF therapy, specifically bevacizumab in Sorsby fundus dystrophy.

Methods :
A 5-year retrospective case series was undertaken. All patients with a mutation in tissue inhibitor of metalloproteinases-3 (TIMP3) for Sorsby fundus dystrophy treated with intra-vitreal bevacizumab injections and at least five years follow-up were included. Consent for therapy was gained from all participants. Primary outcomes were changes in best-corrected visual acuity (BCVA), central macular thickness (CMT) , presence of sub-retinal fluid and macular scar on OCT. Data was analysed using a linear general model in SPSS.

Results :
Nine patients were recruited and five included in the study. The mean and median number of intra-vitreal bevacizumab injections per eye was 16 and 6. At presentation BCVA was 0.1 +/-0.1 LogMAR units (mean+/- standard deviation) and CMT 242 +/-36μm. At five years BCVA was 0.65+/-0.42 LogMAR units and CMT 205+/-27μm. The association between change in CMT and intra-vitreal bevacizumab injections was significant (p=0.028). Persistence of sub-retinal fluid was significantly associated with a reduction in BCVA (p=0.001). Use of bevacizumab therapy in the presence of sub-retinal fluid was significantly associated with improvement in VA (p=0.027). There was, however, a linear decrease in VA of approximately 0.1 LogMAR units per year until scar formation.

Conclusions :
In patients with Sorsby fundus dystrophy use of bevacizumab appears to provide a temporary stabilisation in BCVA through reduction in sub-retinal fluid. Its use, however, is of limited value once macular scar formation has occurred. These results suggest that an as required approach to therapy may need to be changed to a treat and extend approach, similar to changes in care pathways now being implemented for choroidal neovascularization associated with age related macular degeneration.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.